Charmed

Apocalypse Not (2x21)

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When a vanquishing spell goes awry while the Halliwells try to destroy the 4 Horsemen of the Apocalypse, Prue and one of the Horsemen become trapped in a vortex. Piper and Phoebe enlist the help of the three remaining Horsemen to free Prue and the fourth Horseman before the vortex closes, and both are killed.